NEED HELP: 1974 1.8L Will Only Start with Brake Clean, Runs with AFM disconnected only Options

[Nor.Cal.914]

Hello everyone,

I have a 1974 1.8L that needs a new fuel pump and the customer purchased this pump from Pelican:

https://www.pelicanparts.com/More_Info/0439...59&DID=4630

I have already figured out the line routing in terms of inlet and outlet, but I do have a few questions about some other aspects. Being that the stock pump is a 3-port pump, first question is, what was the reasoning behind the 3 ports instead of just an inlet and outlet? My first thought was maybe an internal FPR, but I see there is a one in the engine compartment so that doesn't seem to be the case, but please correct me if I'm wrong! Second question involves mounting the pump. I have a 1975 so I'm not as familiar with how the 1974's were setup. This car has the coil style ring bracket around the pump which I'm now trying to figure out if I can utilize to mount the new pump. Main issue of course is the fact that all 3 lines came out on one side of the factory pump, whereas this pump has inlet/outlet on either side.

So my question is, what have you guys done to mount your pumps either in the same location or where did you place it instead of the factory location? Thank you in advance for the help! (IMG:style_emoticons/default/beerchug.gif)

-Christopher

[Nor.Cal.914]

My units have 7 pins!
Check your connector that plugs into the AFM. Does it have 7 recesses (one of which is "un-populated").

If it does, I believe we can make it work.


The flap should ONLY flutter if the engine is being cranked!!!!!

If it's moving at all when the engine is not that's double headed weird!

There's nothing inside an AFM that should move the flap electronically.

Most of the time the extra pin is for fuel pump "on" signal 6 vs 7.
I can work around that easily.
Some run the extra pin for a IAT sensor.
Both are not a requirement for system functionality.

Yes, they are needed for daily operation but not to turn fuel to fire.

The fuel pump drive signal is one of the "normal" failure points and is often bypassed by previous owners.

Most of the time it's a bad contact point inside the AFM and cleaning/adjusting the contact will fix it.

Your deal of no pump with AFM installed and pump with AFM discoed sounds like someone has modified the fuel pump electrical circuit to me.

I also have injector pulse equipment.

I have 10 tons of tools.

Been doing this shit 40+ years...

I can also fix the AC in your daily drivers!

The "way" I'd start diag on your car is to direct drive the pump (jumper with circuit breaker) and get the system running before I attacked the fuel pump circuit.
It's secondary to FI function IMO.

I'd also "base line" the engine with a comp test.

I can usually achieve function with a can of B12 to the point of heating the engine up and/or moving it around.
I hate pushing cars...

If the fuel is poisoned, you have to clear that first!

Suck tank dry, add a quart, suck tank dry again.

Add a gallon, direct drive the fuel pump with the feed hose in the E-compartment discoed into a fuel can. Run a qt of fresh fuel to e compart. Clear the lines.
Hook up feed and disco return. Run a pint through, clear the e-compart lines.

This will clear 98-99% of the bad fuel.

Feed the bad fuel to a daily driver SLOWLY.

My NAV (negative actual value) 97 Chevy van is my poison eater!

In Ft. Worth they will take bad fuel. I haven't found anyone who will take chemicals/fuel/paint in Granbury.

If you need a transfer pump for draining the tank you can use mine.

Simple Facet square fuel pump with long lines. You are welcome to borrow it.

Siphon can work but after you've had a load of varnished fuel in your mouth, you'll never do it again!

MOST IMPORTANT TIP!!!!!!!!!!

There is a chance that the fuel lines in your car have seen leaded fuel, fuel with MTBE in it, and fuel with ethanol in it.

The three additives attack fuel lines in different ways.

The lines ARE NOT to be trusted!!!!!!!!!

My 75 currently has a low-pressure fuel system with a single progressive carb on it.

The "hard lines" in the tunnel are PLASTIC!!!!!

These are very tough, but I will not change back to FI until I change those critters out with steel lines.

Tangerine Racing is a good source for the lines. All pre-bent and nicely done.

If you have a big ass fire extinguisher next to the car, ready to go, You WILL NOT have a problem.

If you don't...

My 914 will ALWAYS have an extinguisher in the car.
mb911 has a nice bracket for mounting a small one.

Rick,

My AFM connector housing is 6 pins only, no open slots in there. The flap only moves when the engine is cranking, sorry I should've specified in my previous post. I'm trying to wrap my head around what this thing is doing, because it doesn't make much sense. If I move the flap with my finger, I can get the dual relay to activate and turn on the fuel pump, but for whatever reason, when the AFM is connected, the relay never activates and never turns the pump on. The amount of movement needed to activate the relay with my finger seems equal to, if not even less than, what is happening to the flap when the engine is cranking. I don't see any change in fuel pressure with the AFM plugged in and I can't hear the relay click, but I'll have to go back and put my hand on it to see if it is in fact receiving the signal or not.

In regards to the fuel pump circuit, nothing has changed other than I installed an aftermarket 2-port in-line pump. Wiring did not change at all other than to put ring terminals on instead of the OEM connector. As I mentioned previously, I know the pump is working as I can see my pressure and it remains constant while the engine is running, I'm just having issues with actually getting the engine to start on its own without brake clean down the intake.

Fuel was absolutely shot, smelled like varnish. I don't know how long the car was actually sitting, we were told 8-9 months, but based on the condition of the fuel, I'd say it was much longer than that. I completely drained the tank to empty, filled with about 5 gallons of fresh gas and pumped it through the system. I no longer smell the varnish and I've verified that by pulling the return line where it smells like fresh gas now. Not to say that the bad fuel didn't do any damage to the injectors or anything else.

Fuel lines have not been replaced on any portion of the car that I can see. I will be replacing all of the lines from the plastic lines through the entire engine once I get this thing running properly.

Thank you very much for the information! I will be in touch about the parts. Tonight I will be studying up on the L jet system to try and get a better understanding of how it all works for when I get back on the car.

-Christopher